However, Bilic is optimistic that his side could emerge from their form slump, beginning with a victory at their new stadium on Sunday.
"We have two massive games coming up and this is a great opportunity for us to get out of the trouble we are in," Bilic told reporters on Friday.
"It will bring back the confidence and the belief if we can get the victories.
"The reaction has been there in training and we always train hard. We have to do that in games and for 90 minute.
"Southampton got a good victory in Europe last week and it will be another hard game for us."
Bilic added that left back Arthur Masuaku was expected to be out of action for at least six weeks due to ligament damage, but defenders Winston Reid and Alvaro Arbeloa were back in training.
"It is not good news and both our left backs have damaged their ligaments. The injuries are not ideal but we will still have a good team."
The Croat, however, was pleased about the progress of injured duo Andy Carroll and Aaron Cresswell.
"I saw reports that Andy Carroll had a setback but that is totally false. We are expecting him and Aaron Cresswell back after the (international) break."
(Reporting by Nivedita Shankar in Bengaluru; Editing by John O'Brien)
